It is our overall objective to elucidate the biochemical and genetic basis underlying disorders of organic acid metabolism. The study of various acyl dehydrogenases and disorders due to the deficient activity of these enzymes (human acyl CoA dehydrogenase mutants) such as isovaleric acidemia, glutaric aciduria type II, and ethylmalonic-adipic aciduria are the major objectives of the present proposal. A number of new questions concerning the existence of some hitherto unknown enzymes and electron carrier proteins, substrate specificity, reaction mechanisms, and molecular homology and heterogeneity of varius acyl CoA dehydrogenases have been raised from studies of the human acyl CoA dehydrogenase mutants. With these proposed studies, we hope to gain new insight into the molecular structure and function on the various acyl CoA dehydrogenases and to obtain information for a clearer understanding of the biochemical basis of the human acyl CoA dehydrogenase mutants. Individual projects are as follows: a. Purification and characterization of various acyl CoA dehydrogenases from animal and human liver. b. Studies on the mechanisms of dehydrogenation and electron transport from acyl CoAs. c. Studies of the biochemical and genetic mechanisms of human acyl CoA dehydrogenase mutants.